OOS 20-2 - Enhanced dispersal and spread of an invasive thistle under climate change

Wednesday, August 10, 2011: 8:20 AM
16B, Austin Convention Center
Rui Zhang, Harvard Forest, Harvard University, Petersham, MA, Eelke Jongejans, Radboud University Nijmegen, Nijmegen, Netherlands and Katriona Shea, Department of Biology, The Pennsylvania State University, University Park, PA

Global warming and shifted precipitation regimes increasingly affect species abundances and distributions worldwide. Studying the responses of invasive species, which share traits such as high dispersal ability and flexible life histories, may help us to understand the potential magnitude and underlying causes of such changes. Here we show that an invasive species’ demography, dispersal, and spread can be strongly affected by climate change.


In our experiments, manipulated warming not only improved emergence, survival, and reproduction of an invasive thistle, Carduus nutans, but also elevated maternal plant height at flowering - a crucial life history trait that determines seed dispersal distances. Using spatial population models, we demonstrate that these empirical warming effects on demographic vital rates, and dispersal parameters, greatly exacerbate invasion speed. Using a spread rate decomposition technique (c*-LTRE), we find that changes in plant height contribute most to increased invasion. Therefore the potential for modified dispersal should not be overlooked when examining plant responses to climate change.  Species that suffer reduced dispersal ability may be more likely to experience range contraction and eventual extinction, while invasive species may become more problematic under changing climate. Modeling methods that combine both demographic and dispersal responses can provide insights for conservation, restoration, and invasion management in both current and future climates.

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